net: mdio: ipq4019: Separate C22 and C45 transactions

The ipq4019 driver can perform both C22 and C45 transfers.  Create
separate functions for each and register the C45 versions using the
new driver API calls.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>